Apparatus for and method of facilitating the stripping of cans from a punch and the article formed thereby

ABSTRACT

This disclosure relates to apparatus for and a method of facilitating the stripping of a can body or a like cup-shaped article from a wall ironing punch by applying radially directed circumferentially spaced forces against the can body exterior as it moves with the punch whereby lateral or circumferential flow of the can body material is produced along axially extending portions of the can body which increases the circumferences of the can body to facilitate the subsequent stripping thereof from the punch.

0 United States Patent 1 [111 3,733,889 Hansson [4 1 May 22, 1973 54] APPARATUS FOR AND METHOD 01 2,083,698 6/1937 Engelbertz ..72 349 FACILITATING THE STRIPPING 0 1,122,753 12/1914 Holinger ..72/349 1,156,972 10/1915 Carlson ..72/349 CANS FROM A PUNCH AND THE 1,985,833 12/1934 Lampart.... ..72/348 ARTKCLE FORMED THEREBY 2,901,995 9/1959 Lavigne ..72 348 [75] Inventor: Ants Hanson, Evansmn, m 3,581,539 6/1971 Lauener ..72 349 [73] Assignee: Continental Can Company, 1nc., Pri r Ex iner Richai-d J Herbst New York, NY. AttorneyCharles E. Brown et a1. [22] Filed: Dec. 15, 1971 ABSTRACT [21] Appl 208374 This disclosure relates to apparatus for and a method of facilitating the stripping of a can body or a like cup- [52] U.S. Cl ..72/344, 72/348 h p r i l fr m a wall ironing punch by applying [51] Int. Cl. ..B21d 45/00 radially directed circumfefentially Spaced forces 58 Field 01 Search ..72/348, 349, 344, against the can y exterior as it moves with the 72/345 346 punch whereby lateral or circumferential flow of the can body material is produced along axially extending [56] References Cited portions of the can body which increases the circumferences of the can body to facilitate the subsequent UNITED STATES PATENTS stripping thereof from the punch.

1,422,974 7/1922 Higgins ..72/348 17 Claims, 9 Drawing Figures APPARATUS FOR AND METHOD OF FACILITATING THE STRIPPING OF CANS FROM A PUNCH AND THE ARTICLE FORMED THEREBY The present invention is directed to the art of forming drawn and/or wall ironed cans, can bodies, or like containers preferably though not necessarily from metallic material by conventional drawing rings, wall ironing rings, and associated punches. Typical of such apparatus are commonly assigned US. Pat. Nos. 3,478,563 and 3,491,575, issued to John S. Bozek and Richard E. Prendergast et al. on Nov. 18, 1969, and Jan. 27, 1970, respectively.

In the drawing and wall ironing of can bodies as exemplified by the above-noted patents, a difficult problem is that of stripping the can bodies from the wall ironing punch. In the wall ironing process a dish or cup aligned with a punch is forced by the movement of the punch through drawing and/or ironing rings resulting in the elongation of the cup and a reduction in the wall thickness to form the one-piece can body. The can or can body then must be pushed off the punch or held while the punch is retracted therefrom, or a combination of both. This normally is done with compressed air introduced through an appropriate port in the punch into the can body interior or by an external mechanical stripper which grips the edge of the can prior to the retraction of the punch, or by a combination of these or similar means. The force required to strip the can bodies from the punch may be 1,000 lbs., or higher. One reason for such high a stripping force is that in the ironing process the body wall of the can is extruded into small asperities of the exterior punch surface. Another reason is that during the high speed forming of the cup to the can the zone of deformation between the forming rings and the punch is momentarily heated to a high temperature, perhaps several hundred degrees, and upon cooling the can body contracts around the punch creating a high circumferential tensile stress or hoop stress in the can body wall. Therefore, if such a can body is stripped from the punch, it is not unusual that the inside diameter of the body wall becomes significantly smaller than the punch diameter.

The present invention whether considered from its apparatus or method aspects is directed to a novel manner of loosening the can body on the punch toward the end of the wall ironing stroke of the punch so that the can body can more easily be removed from the punch by conventional means, i. e., compressed air, mechanical strippers, or combinations thereof. This loosening is accomplished by drawing or rolling one or more axial or longitudinal depressions or flats in the body wall whereby at each flat the metal is displaced laterally away from the flat. The result is an increase in the can body diameter, i. e., a loosening of the can body on the punch.

The principle of the invention thus far described is based on the phenomenon known as spread" in rolling and drawing of metals. It is known, for example, that wire can be flattened by longitudinal rolling without increasing its length. The metal displacement is lateral, not longitudinal, and this is termed spread". Therefore, because of spread the metal flow during the drawing, ironing or rolling of the flats on the body wall will be predominantly lateral as there will be very little flow or elongation along the length (longitudinal or axial) of the can body.

In keeping with the foregoing, it is a primary object of this invention to provide a novel apparatus for employing the phenomenon of spread to increase can body inner diameter to facilitate the stripping thereof from an associated punch, the apparatus including means for moving the punch and the can body carried thereby in a first direction, and means for increasing the internal circumference of the can body along at least a portion of its axial length by applying a radial force to the body wall between interior and exterior surfaces thereof during the movement of the punch in the first direction whereby due to circumferential material flow or spread the diameter of the can body is increased and it may thereby be more readily stripped form the punch by conventional means.

A further object of this invention is to provide a novel apparatus of the type heretofore set forth wherein the particular means for increasing the can body internal circumference may be, for example, an annular member defining an opening through which the punch moves during its ironing stroke with the opening having at least two bearing surfaces in parallel relationship or a polygon whereby the bearing surfaces and an exterior surface of the punch cooperate to flow the material of the can body disposed therebetween circumferentially to obtain increased internal can body diameter and, of course, circumference.

A further object of this invention is to form such internal circumference increasing means in the form of a number of circumferentially spaced threaded elements appropriately supported in exterior surrounding relationship to the punch whereby the degree of increase in can body internal circumference can be varied by threading or unthreading the threaded elements to vary the flow supply to the can body in conjunction with the punch resulting in a variation in spread and thus a variation in can body inner circumference.

A further object of this invention is to provide the circumference increasing means in the form of a number of circumferentially spaced elements mounted exteriorly of the punch for rotation as, for example, in the form of balls, rollers or the like.

Still another object of this invention is to provide the circumference increasing means as a number of force applying elements secured to a last of the wall ironing rings with the mounting being rigid or deflectable.

With the above and other objects in view that will hereinafter appear, the nature of the invention will be more clearly understood by reference to the following detailed description, the appended claimed subject matter, and the several views illustrated in the accompanying drawings.

IN THE DRAWINGS FIG. 1 is a fragmentary side elevational view with portions broken away for clarity, and illustrates a can body carried by a punch through circumference increasing means which causes the formation of flats axially of the can body to increase its internal circumference and diameter.

FIG. 2 is a radial sectional view through the punch of FIG. 1 looking downwardly, and illustrates the circumference increasing means in the form of an annular member having an opening of a hexagonal configuration with the six sides or surfaces thereof serving as means for bearing against the can body wall to effect the spread thereof and form six axial flats of reduced wall thickness.

FIG. 3 is an enlarged fragmentary sectional view taken generally along line 3-3 of FIG. 1, and more clearly illustrates the manner in which the material flows between adjacent surfaces of the hexagonal opening resulting in the reduction of wall thickness thereat and corresponding bulging of the unrestrained can body material therebetween.

FIG. 4 is a highly enlarged fragmentary sectional view taken generally along line 4-4 of FIG. 3 after the can body has passed through the annular member, and illustrates a reduced circumferential area of the punch which functions as means to prevent the forming of the flats in the upper eventual flange area of the can body.

FIG. 5 is a fragmentary sectional view taken radially through the punch and another circumference increasing means, and illustrates the latter in the form of a number of circumferentially spaced threaded elements for adjusting the distance between bearing surfaces thereof and the punch exterior to vary the increase in can body internal circumference.

FIG. 6 is a view similar to FIG. 5 taken through another apparatus, and illustrates the circumference increasing means in the form of a plurality of balls in circumferentially spaced relationship to each other.

FIG. 7 is a view similar to FIGS. 5 and 6 taken through another circumference increasing means of this invention, and illustrates the latter as being a number of circumferentially spaced rollers.

FIG. 8 is a fragmentary axial sectional view taken through another apparatus of this invention, and illustrates a last of a plurality of wall ironing rings and one of a plurality of flat forming elements deflectably or yieldably carried thereby in circumferential spaced relationship.

FIG. 9 is a top plan view of another annular member similar to FIG. 2, and illustrates the circumference increasing means as a plurality of radially inwardly directed fingers having relieved areas therebetween for accommodating those portions of a can body bulge by circumferential material flow or spread.

A novel apparatus constructed in accordance with this invention is illustrated in FIGS. 1 through 4 of the drawings, and is generally designated by the reference numeral 10. The apparatus 10 includes a punch or mandrel 11 which is moved in a first direction indicated by the solid unnumbered arrow by conventional means during its work or ironing stroke while being retracted by the same means in an opposite direction, as indicated by the phantom outline unnumbered arrow in this same figure. Reference may be made to the Prendergast et al patent for specific means for reciprocating the punch 11 in the manner described, as well as to this same patent and the noted patent to Bozek for draw ring or wall ironing ring structure, indicated in FIG. 1 by the radially inwardly directed unnumbered solid line arrows.

The punch l l is constructed from steel or similar metallic material, and includes a major body portion 12 having an exterior surface 13 of a generally cylindrical configuration of a predetermined diameter which may in some cases taper slightly from top to bottom as viewed in FIG. 1. An upper portion 14 of the punch 11 is reduced in circumference by means of a frustoconical surface or shoulder 15 above which the portion 14 is of a lesser diameter and circumference than that of the major punch portion 13. The function of this reduction in circumference at the portion 14 will be made more apparent hereinafter.

Supported by conventional means (not shown) adjacent and in surrounding relationship to the punch 11 is means 20 for increasing the internal circumference of a cup-shaped article C, such as a metallic can, can body or similar container having a body wall B and an integral bottom end E, during the downward movement of the punch 11 and the can C therethrough. The circumference increasing means 20 is an annular element or member 21 having an opening 22 of a generally hexagonal configuration defined by flat bearing surfaces 23 through 28. Though six surfaces 23 through 28 are illustrated, it is to be understood that more or less than this number may be provided and in accordance with this invention the bearing surfaces may range from one to a polygon but less than a circle, although preferably the minimum number will be maintained at two with the two surfaces in diametrically opposed parallel relationship to avoid side thrust during operation which might be detrimental to the tooling. However, irrespective of the number of bearing surfaces involved, an important requirement is the provision of open spaces 31 through 36 therebetween for receiving bulged portions of the can body C as material flows laterally or circumferentially in the areas of the can body C between the surfaces 23 through 28 and the exterior surface 13 of the punch 1 1 as the latter descends through the circumference increasing means as will be more apparent from FIG. 3 to which attention is now directed.

Prior to being drawn through the circumference increasing means 20 to the position shown in FIG. 1, the can body C had passed through one or more conventional drawing and/or ironing rings which elongated the initial length of the cup-shaped blank and reduced the wall thickness thereof. During this high speed forming, a deformation zone within the ironing ring is momentarily heated to a high temperature and upon cooling the can contracts around the punch creating a high circumferential tensile stress or hoop stress in the body wall B and, in addition, the metal is extruded by the ironing rings into small asperities of the surface 13. Thus, prior to being introduced into the circumference increasing means 20 the can body C is held so tightly upon the punch that the force required to strip the can body C therefrom could be, absent the present invention, 1,000 lbs., or higher. However, upon being forced through the circumference increasing means 20, a number of axially or longitudinally extending flats F corresponding in number to the number of bearing surfaces 23 through 28 are formed in an exterior surface of the can body C from a point adjacent the bottom of the body wall B and running toward but terminating short of its top. The flats F are formed because the distance between the axis of the punch 11 and any one of the bearing surfaces 23 through 28 is less than the exterior radius of the major portion 13 of the punch 11. Thus, as the punch 11 drives the container C through the opening 22, the surfaces 23 through 28 progres sively form the flats F from bottom to top causing metal to flow laterally or circumferentially due to the phenomenon known as spread with the metal thus displaced forming axially extending bulges or humps H, one between each pair of flats F which are freely received in the spaces 31 through 36. Thus, due to the reduction in can body wall thickness across the width W of the flats and the lateral flow of material, the inner circumference and diameter of the body wall B is increased and upon complete passage of the can C through the means 20 the humps H spring back slightly with the result that the can C is now held relatively loosely upon the punch 11 and can be removed therefrom by an external mechanical stripper (not shown), a blast of compressed air conducted into the can body interior through a port (not shown) in the punch 11, or combinations thereof.

It will be noted from FIG. 4 that a circumferential area adjacent a top terminal edge T of the can body is devoid of the flats F and remains of a wall thickness corresponding to that of the can body wall B after the latter has passed to the last ironing ring. Since an end is to be double seamed to the upper portion of the can C, it is desired to maintain this upper circumferential area or flange area as strong as possible for double seaming, and this is accomplished due to the reduced circumferential portion 14 of the punch 11 as a result of the shoulder 15. As viewed in FIG. 1, as the punch 11 continues downwardly, the shoulder 15 and the portion 14 progressively pass into and through the opening 22 and the upper portion of the can body B is no longer backed by the larger circumference portion 13 of the punch 11; hence the terminal end portion of the can body B is temporarily deflected radially inwardly toward the surface 14 whereupon the formation of the flats F is terminated short of the terminal edge T. FIG. 4 illustrates the manner in which the upper end portion of the body B rebounds away from the surface 14 after passing completely through the opening 22.

Many factors enter into the degree of loosening accomplished by the apparatus 10 but it has been found that in the production of No. 211 steel cans, for instance, the elastic shrinkage in can diameter is about 5 mils after stripping the can from a conventional punch in a conventional manner absent the practice of the present invention. It is, therefore, necessary to increase the can circumference in keeping with the present invention by 16 mils in order to reduce the hoop stresses or circumferential stresses to zero. It can be readily calculated that with six flats or bearing surfaces 23 through 28, a 9 percent wall thickness reduction at each flat would displace enough metal to obtain such a desired increase in circumference if the width W of each flat is between 4 mils to 3.65 mils, for example. Generally speaking, the wall reduction at the flats F as compared to original wall thickness should be on the order of 5 percent. From this it should be appreciated that the flats F illustrated in FIGS. 1 through 3 are highly exaggerated in width and in actual practice they appear as very narrow faint longitudinal lines along the outside of the can body wall B and thus are not objectionable from the viewpoint of appearance or esthetic value, particularly since the can B is base coated and lithographed. Moreover, though the flats F are shown to be straight upon their exterior surface they could be slightly concave or convex although internally each flat corresponds to the arcuate configuration of the exterior punch portion 13.

Reference is now made to FIG. 5 of the drawings which illustrates another can body circumference increasing means 40 in the form of an annular element or member 41 which surrounds the exterior of the punch 11, but in lieu of a one-piece construction, a plurality of circumferentially spaced threaded elements 42 having end bearing or force applying surfaces 43 are threaded into radially threaded bores 44 of the annular member 41. Assuming six such elements 43 are carried by the annular element 41 the can body C will, as in the case of FIGS. 1 through 4, be provided with six flats. However, the threaded elements 42 perform the additional function of permitting the degree of can body circumference (internal) to be selectively varied. If, for example, the element 42 and the remaining elements not shown are rotated such to retract the surface 43 away from the surface 13 of the punch 11 less force would be created, less bow I-I would be created, and thus a lesser increase in internal circumference would be achieved while opposite rotation of the threaded element 42 and others not shown would cause a greater increase in internal can body circumference.

Another means 50 for increasing the internal circumference of the wall B of a can body C is shown in FIG. 6 and includes an annular element or ring 51 surrounding the punch 11, just as in the case of the means 20, 40. The annular element 51 is provided with a plurality of openings 52 formed in spaced relationship about its circumference with a steel ball 53 being received in each opening 52 and held therein by conventional retaining means 54. In operation the flat F formed thereby is identical to the flats formed in the manner heretofore described except that the flat of FIG. 6 is of an outwardly opening concave configuration.

Other means (FIG. 7) for increasing internal circumference of a can body wall B is again formed by the use of an annular element or member 61 having secured in spaced relationship therealong a number of cylindrical rollers 62 journalled for rotation on shafts 63 of harnesses 64 secured to the annular member 61 by bolts 65 or similar conventional means.

The embodiments of the invention illustrated in FIGS. 5 through 7 additionally function to reduce wear and/or provide adjustment therefor. For example, under prolonged usage the surface 43 of the element 42 would wear but upon advance toward the punch this wear can be readily compensated for at minimal downtime. Wear is reduced by the ball 53 if clamped to the annular member 51 to permit rotation during the ironing operation, just as in the case of the roller 62. However, if the clamping means 54 is tightened to prevent rotation of the ball 53, wear on its surface can be compensated for by simply loosening the clamping means 54, rotating the ball 53 to present an unused surface toward the punch 11, and thereafter reclamping the clamping means 54 tightly.

Each of the means 20, 40, 50 and 60 operates on the principle of a fixed gap between the bearing surfaces 23 through 28, 43, 53, 62 and the exterior surface 13 of the punch 11. However, the invention is also applicable to operating on the principle of a fixed force. That is, comparable bearing surfaces could be flexibly mounted so as to exert a certain pressure or force on the can body wall B to produce a flat of a particular dimension, and in this regard reference is made to FIG. 8 which illustrates one of a plurality of circumference increasing means '70 removably secured by a threaded bolt 71 to an ironing ring 72 or the last of a plurality of ironing rings secured to a surface S in a conventional manner. The means 711 includes a piece of angle bar 73 of a generally L-shaped configuration reduced in cross section at an area 74 to permit an end 75 thereof carrying a bearing element 76 to flex or yield depending upon the looseness desired. This force may be on the order of 50 500 pounds depending on the can body material, wall thickness, and desired degree of looseness, but the deflection of the flute forming bearing element 76 would be very small (on the order of l 3 mils).

In further keeping with this invention, any one of the means 20, 40, 50, 60 can likewise be substituted for the means 70 and thus be mounted upon or immediately adjacent to the last of the ironing rings 72. This permits excellent can control since the can C is still engaged by the last ironing ring 72 when the flats are being formed by the bearing elements 76. Ease of access and adjustment is, of course, also maintained.

FIG. 9 illustrates means 80 in the form of an annular member 81 for increasing internal can body circumference in essentially the manner heretofore described relative to FIGS. 1 through 4. However, in this case the annular member 81 was initially a standard wall ironing ring from which segments of material have been removed as at 82 to form a generally circular opening into which projects a number of bearing elements 83 whose terminal faces 84 form the flats F in the can body C. The size and number of the projections 83 may vary as well as the removed segments or voids 82.

While preferred forms and arrangements of parts have been shown in illustrating the invention, it is to be clearly understood that various changes in details and arrangement of parts may be made without departing from the spirit and scope of this disclosure.

I claim:

1. Apparatus for drawing cup-shaped articles comprising a reciprocating punch, means for moving said punch and a cup-shaped article carried thereby in a first direction through at least one circular female die means for axially elongating said cup-shaped article and undesirably tightly adhering the elongated cupshaped article to the punch due to created hoop stresses, means disposed immediately after said at least one circular female die means for increasing the internal circumference of said elongated cup-shaped article along at least a continuous portion of its axial length by circumferential flow of the material thereof during the movement of said punch in said first direction whereby said elongated circumferentially increased cup-shaped article may be more readily stripped from said punch, and means for stripping said elongated circumferentially increased cup-shaped article from said punch immediately after the operation of said circumference increasing means and absent the use of reforming means beyond said circumference increasing means as viewed in said first direction.

2. The apparatus as defined in claim 1 wherein said circumference increasing means is additionally operative for reducing the thickness of the cup-shaped article at the area of circumferential material flow.

3. The apparatus as defined in claim 1 wherein at least two such circumference increasing means are provided in circumferential spaced relationship to each other.

4. The apparatus as defined in claim 1 wherein at least two such circumference increasing means are provided in circumferentially aligned and spaced relationship to each other.

5. Apparatus for facilitating the stripping of a cupshaped article from a punch comprising means for moving a punch adapted to carry a cup-shaped article of a predetermined internal circumference in a first direction, means for increasing the internal circumference of said cup-shaped article along at least a portion of its axial length by circumferential flow of the material thereof during the movement of said punch in said first direction whereby said cup-shaped article may be more readily stripped from said punch, means for selectively varying the amount of increase in internal circumference created by said circumference increasing means.

6. The apparatus as defined in claim 1 wherein said circumference increasing means is an element supported to bear against an exterior surface of the cupshaped article as the punch moves in said first direction.

7. The apparatus as defined in claim 1 wherein said circumference increasing means is an element supported to bear against an exterior surface of the cupshaped article as the punch moves in said first direction, and said element includes a bearing surface of a rounded configuration.

8. The apparatus as defined in claim 1 wherein said circumference increasing means is an element supported to bear against an exterior surface of the cupshaped article as the punch moves in said first direction, and said element includes a bearing surface of a flat configuration.

9. The apparatus as defined in claim I wherein said circumference increasing means is an element supported to bear against an exterior surface of the cupshaped article as the punch moves in said first direction, and means mounting said element for rotation.

10. The apparatus as defined in claim 1 wherein said circumference increasing means is an element supported to bear against an exterior surface of the cupshaped article as the punch moves in said first direction, and said element is an annular member through which the punch passes when moved in said first direction.

11. The apparatus as defined in claim 1 wherein said circumference increasing means is an element supported to bear against an exterior surface of the cupshaped article as the punch moves in said first direction, said element is an annular member through which the punch passes when moved in said first direction, and an interior surface of said annular member defines said circumference increasing means.

12. The apparatus as defined in claim 1 wherein said circumference increasing means is an element supported to bear against an exterior surface of the cupshaped article as the punch moves in said first direction, said element is an annular member through which the punch passes when moved in said first direction, and said circumference increasing means is internally of said annular member.

13. Apparatus for facilitating the stripping of a cupshaped article from a punch comprising means for moving a. punch adapted to carry a cup-shaped article of a predetermined internal circumference in a first direction, means for increasing the internal circumference of said cup-shaped article along at least a portion of its axial length by circumferential flow of the material thereof during the movement of said punch in said first direction whereby said cup-shaped article may be more readily stripped from said punch, each circumference increasing means is a surface supported for bearing against an exterior surface of the cup-shaped article as the punch moves in said first direction, an ironing or draw ring through which said punch passes when moved in said first direction, said ring is upstream of said surfaces relative to said first direction of movement, and means for securing at least one of said surfaces to said ironing or draw ring.

14. Apparatus for facilitating the stripping of a cupshaped article from a punch comprising means for moving a punch adapted to carry a cup-shaped article of a predetermined internal circumference in a first dicup-shaped article at the area of circumferential material flow, and said punch includes means for preventing the operation of said circumference increasing means prior to the termination of movement of said punch in said first direction.

15. The apparatus as defined in claim 14 wherein said preventing means is a circumferential area of reduced" circumference as compared to the circumference of a major working portion of the punch.

16. The apparatus as defined in claim 1 wherein said punch includes means for preventing the operation of said circumference increasing means prior to the termination of movement of said punch in said first direction.

17. The apparatus as defined in claim 15 wherein said preventing means is a circumferential area of reduced circumference as compared to the circumference of a major working portion of the punch. 

1. Apparatus for drawing cup-shaped articles comprising a reciprocating punch, means for moving said punch and a cup-shaped article carried thereby in a first direction through at least one circular female die means for axially elongating said cup-shaped article and undesirably tightly adhering the elongated cup-shaped arTicle to the punch due to created hoop stresses, means disposed immediately after said at least one circular female die means for increasing the internal circumference of said elongated cupshaped article along at least a continuous portion of its axial length by circumferential flow of the material thereof during the movement of said punch in said first direction whereby said elongated circumferentially increased cup-shaped article may be more readily stripped from said punch, and means for stripping said elongated circumferentially increased cup-shaped article from said punch immediately after the operation of said circumference increasing means and absent the use of reforming means beyond said circumference increasing means as viewed in said first direction.
 2. The apparatus as defined in claim 1 wherein said circumference increasing means is additionally operative for reducing the thickness of the cup-shaped article at the area of circumferential material flow.
 3. The apparatus as defined in claim 1 wherein at least two such circumference increasing means are provided in circumferential spaced relationship to each other.
 4. The apparatus as defined in claim 1 wherein at least two such circumference increasing means are provided in circumferentially aligned and spaced relationship to each other.
 5. Apparatus for facilitating the stripping of a cup-shaped article from a punch comprising means for moving a punch adapted to carry a cup-shaped article of a predetermined internal circumference in a first direction, means for increasing the internal circumference of said cup-shaped article along at least a portion of its axial length by circumferential flow of the material thereof during the movement of said punch in said first direction whereby said cup-shaped article may be more readily stripped from said punch, means for selectively varying the amount of increase in internal circumference created by said circumference increasing means.
 6. The apparatus as defined in claim 1 wherein said circumference increasing means is an element supported to bear against an exterior surface of the cup-shaped article as the punch moves in said first direction.
 7. The apparatus as defined in claim 1 wherein said circumference increasing means is an element supported to bear against an exterior surface of the cup-shaped article as the punch moves in said first direction, and said element includes a bearing surface of a rounded configuration.
 8. The apparatus as defined in claim 1 wherein said circumference increasing means is an element supported to bear against an exterior surface of the cup-shaped article as the punch moves in said first direction, and said element includes a bearing surface of a flat configuration.
 9. The apparatus as defined in claim 1 wherein said circumference increasing means is an element supported to bear against an exterior surface of the cup-shaped article as the punch moves in said first direction, and means mounting said element for rotation.
 10. The apparatus as defined in claim 1 wherein said circumference increasing means is an element supported to bear against an exterior surface of the cup-shaped article as the punch moves in said first direction, and said element is an annular member through which the punch passes when moved in said first direction.
 11. The apparatus as defined in claim 1 wherein said circumference increasing means is an element supported to bear against an exterior surface of the cup-shaped article as the punch moves in said first direction, said element is an annular member through which the punch passes when moved in said first direction, and an interior surface of said annular member defines said circumference increasing means.
 12. The apparatus as defined in claim 1 wherein said circumference increasing means is an element supported to bear against an exterior surface of the cup-shaped article as the punch moves in said first direction, said element is an annular member through which the punch passes when moveD in said first direction, and said circumference increasing means is internally of said annular member.
 13. Apparatus for facilitating the stripping of a cup-shaped article from a punch comprising means for moving a punch adapted to carry a cup-shaped article of a predetermined internal circumference in a first direction, means for increasing the internal circumference of said cup-shaped article along at least a portion of its axial length by circumferential flow of the material thereof during the movement of said punch in said first direction whereby said cup-shaped article may be more readily stripped from said punch, each circumference increasing means is a surface supported for bearing against an exterior surface of the cup-shaped article as the punch moves in said first direction, an ironing or draw ring through which said punch passes when moved in said first direction, said ring is upstream of said surfaces relative to said first direction of movement, and means for securing at least one of said surfaces to said ironing or draw ring.
 14. Apparatus for facilitating the stripping of a cup-shaped article from a punch comprising means for moving a punch adapted to carry a cup-shaped article of a predetermined internal circumference in a first direction, a plurality of means for increasing the internal circumference of said cup-shaped article along at least a portion of its axial length by circumferential flow of the material thereof during the movement of said punch in said first direction whereby said cup-shaped article may be more readily stripped from said punch, said plurality of means being disposed exteriorly of said punch and in circumferential spaced relationship to each other, said circumference increasing means are additionally operative for reducing the thickness of the cup-shaped article at the area of circumferential material flow, and said punch includes means for preventing the operation of said circumference increasing means prior to the termination of movement of said punch in said first direction.
 15. The apparatus as defined in claim 14 wherein said preventing means is a circumferential area of reduced circumference as compared to the circumference of a major working portion of the punch.
 16. The apparatus as defined in claim 1 wherein said punch includes means for preventing the operation of said circumference increasing means prior to the termination of movement of said punch in said first direction.
 17. The apparatus as defined in claim 15 wherein said preventing means is a circumferential area of reduced circumference as compared to the circumference of a major working portion of the punch. 